Hi Aaron,
Optimization solvers often does not work with "UseParallel == true" option when a Simulink model is part of objective/fitness function evaluation. This has to do with the Simulink model not being available on PCT engines in a reliable way when using PARFOR. Optimization solvers use PARFOR to evaluate the objective function in parallel. Hence, no support for Simulink when using GA or other optimization solvers. See limitations here:
https://www.mathworks.com/help/gads/how-solvers-compute-in-parallel.html
In your case, it is likely that GA is getting incorrect reward (fitness) value when running in parallel, so the result is useless.
If you want to make use of PCT with GA for Simulink, you will have to do your own parallel evaluation using PARSIM. See here:
When you can evaluate your function in parallel, use the option "UseVectorized == true" with GA. This setting will have GA send your objective the entire population to evaluate and you can evaluate them using PARSIM
I do not have an example using GA but I have something using another solver "surrogateopt". You can use this example to write something for GA. Focus on how the objective function can use PARSIM in this example.
Hth,
Rakesh
